The object of a crop havesting machine called a mower conditioner is to cut a swath of standing crop, condition the cut crop uniformly, and then deposit the conditioned crop in a uniform windrow (or swath) back on the field. To condition the crop, the swath of cut crop is fed through a conditioning zone defined between a pair of conditioning rolls in the machine. The rolls typically have conditioning elements defined about their peripheries and are yieldably biased toward one another to apply sufficient pressure to adjacent portions of the crop stems to crack or crimp the stems as they pass through the zone. Crimping of the stems enhances release of moisture by the stems and curing of the stems at the same rate as the leaves of the stems while the cut and conditioned crop rests in the field. However, the view that the rolls are conventionally configured with cooperating conditioning elements having uniform height and width dimensions which, therefore, define a conditioning zone having uniform dimensions, in order to condition the crop uniformly the swath of crop being fed through the zone needs to be of generally uniform thickness.
Commercial models of mower conditioners often vary in cutting widths from eight to sixteen feet or more while the maximum operative length of the conditioning rolls is generally nine to ten feet. In view of the trend toward use of larger size equipment, a substantial porportion of mower conditioners being used today cut a crop swath which is substantially wider than the length of the conditioning rolls. This necessitates employment of means such as an auger to consolidate the cut crop into a layer of crop which is narrower in width than the swath of standing crop cut from the field. However, in the case of many, if not most, commercial mower conditioner models, the space available in the machine in which to accomplish consolidation of the swath of cut crop is too short to achieve a crop layer having generally uniform thickness. Ordinarily, the crop layer is generally thicker along its opposite longitudinal edge portions, being produced typically by wads of crop, than along its main portion. This problem is especially acute in heavy, wet crop conditions and becomes more severe as the width of the crop swath cut by the machine increases. Frequently, the thicker amount of cut crop feeding into the ends of the conditioning rolls tends to bind and accumulate there, resulting in excessive wear at the ends of the rolls.
In view that the conventional practice is to provide a crop conditioning zone having uniform dimensions, the objective of achieving substantially uniform conditioning of a significantly non-uniform crop layer is generally unattainable. Instead, the greater thickness of the crop layer at its opposite edges causes overconditioning of the crop along the opposite edges and, concurrently overloading of the yieldably biased conditioning rolls. Such overloading at the opposite ends of the rolls causes them to separate and the conditioning zone defined therebetween to enlarge uniformly which, in turn, results in underconditioning of the main portion of the crop layer passing through the zone. As a consequence, the crop layer is conditioned non-uniformly and will later cure non-uniformly in windrow form on the field.